Major roadworks on Llantrisant Road

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Some residents will be aware that Llantrisant Road is to be closed to through traffic towards the end of the month. Rumours have been widely shared - with some fearing that HGV traffic would be diverted through Radyr and Morganstown.

We can now reveal what will actually be happening - following the Community Council's meeting with Cardiff Council earlier today.

Here, to begin with, is Cardiff's statement:

Vital drainage works will be carried out on Llantrisant Road
Llantrisant Road - from the junction with Heol Isaf to Cardiff Road (Creigiau) - will be closed in both directions from 9.30am on July 22nd for approximately three weeks, so vital drainage works can be carried out on the carriageway.

During the closure, the contractor will be carrying out work between 8am and 10pm from Monday to Saturday and from 9am until 10pm on Sundays.

The three week closure is the maximum amount of time that the road will have to close and if the work is completed earlier, residents, businesses and the general public will be notified in advance via an update press release. The work has been scheduled during the summer holiday, as research shows that after children break up from school, the traffic flow reduces significantly.

The Council has put plans in place to minimise disruption to residents and businesses. These include:

• The weight restriction on Heol Isaf will remain in place (except for the usual access arrangements).
• The Council and our contractor have contacted businesses in the area and access will be maintained for both residents and businesses living or operating on Llantrisant Road from the junction with Heol Isaf to the junction with Heol St Y Nyll.
• Residents who live in the Rhydlafar Estate will also be given access in and out of their properties, enabling them to travel along Croft-Y-Gennau Road to get to the south of the city.
• All emergency services have been notified about the closure and protocols will be put in place to ensure that these services can operate effectively.
• All bus operators have also been informed about the closure and any amendments to any services which usually use this route will be clearly advertised on the busoperator’s website.
• Access for both pedestrians and cyclists will be maintained throughout the road closure via a temporary bridge.
• All electronic signs (VMS) will be used within the Cardiff and South Wales Trunk Road Agency (SWTRA) areas, so that advanced notice is given to all road users prior and during the road closure. A signposted diversion route will be in place. Those travelling north out of the city will be advised to travel along the A48 or use Heol Isaf to access the A470.
• Those travelling into Cardiff will be advised to use the M4 motorway. All HGV traffic to current development sites will be diverted along the A48 from Western Avenue.

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So what else do we know?

Is this happening because of Plasdwr?

No. This is a local authority project. The road surface and culvert are substandard just east of Creigiau. The work involved will require excavation of a trench of considerable depth, as well as resurfacing the road - making it impossible to keep the road open, or to open it when the day's work is done.

Cardiff Council has decided​ to undertake the work during the school holidays, when there is less traffic on the road and no school-runs to disrupt. Were the work not done, and the existing culvert collapsed, the road would be flooded - and an unplanned repair could easily take twice as long as the planned, summer-time repair.

What will happen to Heol Isaf?

Cardiff Council will be placing a great many diversion signs across the city and beyond - explaining that Llantrisant Road is closed - and directing traffic along alternative routes. These will include staying on the M4 (and traffic from Rhondda Cynon Taf joining the M4); then leaving the M4 at junction 33 - to drive to the Bay, or to leave at Culverhouse Cross to travel along the A48 towards Western Avenue  (from where HGVs can turn left through Llandaf to approach the Plasdwr construction site).

Traffic will be diverted along Heol Isaf - but the existing weight restriction will remain in place. Even so, Cardiff Council hopes that a lot of traffic will follow the initial diversion onto the A48. The Go-Safe team will attend more often, keeping an eye on the speed of traffic on Heol Isaf. A temporary 20mph limit will not be introduced, because a consultation on a permanent 20mph Order is already underway. Cardiff's legal advice is that a temporary speed limit, imposed during the consultation period for a permanent speed limit, could lead to a legal challenge that the introduction of the temporary limit prejudiced the outcome of the consultation.

I live in Clos Parc Radur. What will happen to me?

After the Heol Isaf / Llantrisant Road roundabout, a chicane will be installed, to emphasise the point that the road ahead is closed. But local traffic and lorries delivering to the Redrow site will still be able to drive in and out of Clos Parc Radur. In fact, you will still be able to drive to St Fagan's this way. The road closure is just before Creigiau.

What if an HGV heading to Merthyr driver gets confused - and arrives at the Heol Isaf / Llantrisant Road roundabout?

A sign placed at the roundabout will instruct them to use the roundabout to make a u-turn and return back along Llantrisant Road.

If Heol Isaf does get busy, will traffic use Bryn Derwen / Drysgol Road /Windsor Avenue as a rat-run? And what about Golf Club Lane?

A sign will be placed at Windsor Road directing traffic along Heol Isaf. The possibility of closing Golf Club Lane for the duration is also being considered - to avoid its use as a rat run.

What about the bus service?

Cardiff Bus services to Radyr and Morganstown will be able to follow their current routes.

What about the emergency services?

They have been fully consulted and have plans in place to cope with the closure.

Will there be any temporary traffic lights near the Heol Isaf / Llantrisant Road junction works during this period?

No. Cardiff have instructed the Plasdwr contractors to keep that stretch of road fully open during the three week period.

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Here's a map showing the closure scheme and related signage. Click on the map to see a full-size copy. (Right-click on the map if you want to download a pdf copy - which you can then expand on you screen, to view more detail). Note - the map shows the Heol Isaf weight restriction being lifted. This is not correct - the weight restriction will not be lifted:

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